docs: def show(self, delete_after=20, scale=10, border=None, color='#000',
               background='#fff'):  # pragma: no cover
          """\
          Displays this QR code.
  
          This method is mainly intended for debugging purposes.
  
          This method saves the output of the :py:meth:`png` method (by default
          with a scaling factor of 10) to a temporary file and opens it with the
          standard PNG viewer application or within the standard webbrowser.
          The temporary file is deleted afterwards (unless `delete_after` is set
          to ``None``).
  
          If this method does not show any result, try to increase the
          `delete_after` value or set it to ``None``
  
          :param delete_after: Time in seconds to wait till the temporary file is
                  deleted.
          """
          import os
          import time
          import tempfile
          import webbrowser
          import threading
          try:  # Python 2
              from urlparse import urljoin
              from urllib import pathname2url
          except ImportError:  # Python 3
              from urllib.parse import urljoin
              from urllib.request import pathname2url
  
          def delete_file(name):
              time.sleep(delete_after)
              try:
                  os.unlink(name)
              except OSError:
                  pass
  
          f = tempfile.NamedTemporaryFile('wb', suffix='.png', delete=False)
          try:
              self.save(f, scale=scale, color=color, background=background,
                        border=border)
          except:
              f.close()
              os.unlink(f.name)
              raise
          f.close()
          webbrowser.open_new_tab(urljoin('file:', pathname2url(f.name)))
          if delete_after is not None:
              t = threading.Thread(target=delete_file, args=(f.name,))
              t.start()